Fork for elevating trucks



Oct. 27, 1953 sso 2,656,943

FORK FOR ELEVATING TRUCKS Filed March 13, 1950 3 Sheets-Sheet l Oct. 27, 1953 H. E. NILSSON FORK FOR ELEVATING TRUCKS 3 Sheets-Sheet 2 Filed March 13, 1950 Oct. 27, 1953 H. E. NILSSON 2,656,943

FORK FOR ELEVATING TRUCKS Filed March 15, 1950 v 3 Sheets-Sheet 3 T I l i 5 I z 2 I 6 6 i I g g g l i 4 i l l l l L i Y w w w Patented Oct. 27, 1953 FORK. FORv ELEVATIN G TRUCKS.

Hans Eric Nilsson, Handol; Sweden; assignor to Aktiebolaget Tegelindustriella Byran, Stocks holm, Sweden, a corporation of. Sweden Application March 13, 1950-, Serial No. 149,391 In Sweden March 31,1949

4 Claims. I

The present invention relates toan arrangement in forks for so-called elevating trucks, and particularly for those trucks which are used for elevating and transporting piles of bricks. In brick depots in which the bricks are piled by meansof elevating trucks, the bricks are usually piled in such a manner that there are formed horizontally extending spaced channels the arms of the truck fork beinginserted in said channels when a pile of bricks is to be elevated. The skid bricks forming the sidewalls and the roof of the channels will, thus serve as temporary sup ports. If trucksprovidedwith forks of the usual type are used for elevating the pile of bricks, only those bricks which form the roof of the channels, and naturally also that part of the pile which is located above said bricks will be elevated, andxthosebrickswhich form the side walls of the channels, will be left. When the pile of bricks located on the truck fork-is to-be deposited, it is thus necessary to provide for spaces in the foundation into which spaces the arms of the fork can be inserted and unloaded from the bricks, This arrangement of the foundation involves heavy manual work at the loading and elevation which in. other.- respects. is mechanized to a great extent. It has been tried to eliminate this inconvenience in different ways. The expedient most close at hand is to try to bring along also those bricks-which? form the side walls of the channels: However; the known devices used for this purpose arerather complicatedand therefore expensive and: unreliable with. respect to; their operation:

The present invention has forits object an improvement thearmsaoff the, truck fork, for elevati galso the supports. forming the side walls of. the. channels, said improved construction being simple and reliable with respect to its operation.

The fork arm of the truck according to the present invention is substantially characterized by a lower plate rigidily connected to the fork, a movable upper plate, and a side wall of flexible material located between said plates on at least one side of the arm, said wall being adapted to bulge outwards from the centre line of the arm when the upper plate is being pressed down against the lower plate.

Different embodiments of the invention are shown by way of example on the accompanying drawings, in which Figs. 1a and 1b are a front view and a side View respectively of a truck fork, Fig. 2 a side view of a truck fork arm, partly in section, Figs. 3 and 4 sections on lines III--III and IVIV respectively of Fig. 2, Figs. 5 to 7 2 are transverse vertical sections through other'fork arms embodying the invention, and Figs. 8 and 9 are fragmentary vertical sections through a fork arm located within a channel between two skid bricks; Fig. 8 showing the fork arm free from the bricks, and Fig; 9 showing the arm elevated to lift the bricks.

Aswill be seen from Fig. 1, the truck fork consists of a back-piece I in. the form of a grating which on its rear side is provided with projections 2 forfixing same; and at the bottom carries the forkarms 3 extending forwards substantially at right angles to the back-piece; As" shown in Fig. 2, the fork arms 3 substantially consist of a lower, stationary plate 4 an upper plate 5' which is movable relatively to thestationarwplate" 4", and elements 6- of flexible material located be-= tween said twoplates. In the" embodiment shown; there a-rethree tubular elements '6 on each side; of the fork arm; However; it is selfevident that: the invention is not restricted to this number.. Between the elements 6 there areprovided guide members for guiding the movement of the movable plate 5. As will be seen' from Fig. 4, said members consist of a cylindrical SOCkEt"1"fi '-ET1 to the lower plated and" ofa pin 3' fitting into; said socket and 'flxed to the upper plate 5'. In. its lower, inner portion? the socket l is provided; with an annular-groove 9' which is open the downwarddirecti'on; and which-at the'topmerges into the normal'sect-ion ofthesocketbymeans'of a shoulder forming astop fora washer I'll fixed? on the pin 82 Theshoulder and the washer act together to limit the upward movement of the pin- 8. In its lowermost positionthe' plate Ehests onthe-plate 4 by means of" theupper edge of the cylindrical guide" member 1* and the upper edge'of a flangel l fixed between the members I in the-lower plate: The I abovementioned guide members are not absolutely necessary in order that the fork arm shall function in the desired manner but they steady the construction which often is of advantage. The guide devices may also be constructed in some other manner without going beyond the scope of the invention.

As shown in Figs. 3 and 7-9, the elements 6 may be substantially oval in cross section when no load is imposed upon the top plate, and designed in such a manner that when the elements are compressed by the weight of the bricks lifted by the upper plate the side walls bulge outwards, so that the oval cross section becomes more round. The symmetric design of the elements involves the advantage that the elements when one of their side walls has be- 3 some too much worn, can simply be turned round so that the wall previously facing the flange Ii will now be directed outwards. As shown, the elements may be hollow but also solid or filled with some yielding material, such as sponge rubher, in order to become more steady. It is also possible to provide leaf springs l6 within the elements, said springs having such an initial tension that they assist in bulging the elements.

Fig. shows a modification of the elements 6 which are made in the form of shallow channels of approximately half oval cross-section, the lower flanges of which are fixed to the lower plate 4 by means of bolts l2 and the upper flanges of which are vulcanized to a plate l3 common to both elements, said plate l3 being provided with a pin l4 fitting into a corresponding recess in the upper plate 5. Fig. 6 shows a modification of the device according to Fig. 5 in which the elements 6 are fixed to both plates 4 and 5 by means of bolts 12.

Fig. 7 shows an embodiment of the fork arm which is intended for the arm located farthest to the left in Fig. 1a. The stationary plate is in this case provided with a vertical plate [5 which is rigidly connected to the first mentioned plate at right angles to the same so that the two plates form an angle-iron. This construction offer an increased steadiness and a better guidance of the movable plate 5 which, when pressed down, can go clear of the upper edge of the wall [5.

The device according to the invention operates in the following manner. The bricks are piled in such a manner on a series of rows of skid bricks that spaced channels are formed, the spaces between the channels corresponding to the distance between the fork arms. When the pile of bricks is to be elevated, the arms are inserted in said channels, see Fig. 8. When the load is being elevated, the movable plate will be pressed downwards due to the compression of the elements 6 until the pressure corresponds to the resistance of these elements or until the plate 5 comes to rests against the flange ll. During this operation the side walls of the elements are pressed or bulged outwards (Fig. 9), so that the elements in two adjacent arms will clamp between them the fundament bricks forming the side walls of the channels. Said bricks will thus follow the other bricks of the pile when the elevation continues. When depositing the pile and lowering the fork the elements 6 will gradually be unloaded and assume their original form while disengaging from the skid bricks which are thus left when the fork is withdrawn. The fork is generally constructed in such a manner that there is room for two bricks standing on edges between the arms.

The elements 6 may be made of rubber or any material possessing the required flexibility and 4 offering sufilcient friction to the bricks in order that it shall be possible to elevate the same under the influence of the pressure exerted by the elements. Thus, the invention is not restricted to the embodiment of the elements disclosed and described, but it also comprises other embodiments.

I claim:

1. In a truck fork for lifting articles stacked on spaced skid supports and also the skid supports; a truck fork frame adapted to be secured to an elevator, and truck fork arms carried by said frame and spaced apart for introduction into the respective channels at opposite sides of a plurality of skid supports; each truck fork arm comprising an upper plate, a lower plate rigidly secured to said truck fork frame, said lower plate being of angular cross-section and having a central leg extending vertically in the direction of said upper plate and terminating short of the underface of said upper plate when said fork arm is unloaded, and means yieldingly supporting said upper plate on and for vertical movement with respect to the lower plate; said supporting means comprising a flexible material wall having a convex surface initially spaced from the adjacent surface of a skid support, said flexible material wall being bowed outwardly into frictional engagement with the skid support by compression of said flexible material wall on lifting of the truck fork to impose a load upon said upper plate and said central leg effecting lifting engagement with the underface of said upper plate.

2. In a truck fork, the invention as recited in claim 1, in combination with means guiding said upper plate for vertical movement.

3. In a truck fork, the invention as recited in claim 1, wherein said flexible material wall is tubular and of substantially oval cross-section when relieved from load.

4. In a truck fork, the invention as recited in claim 1, wherein said flexible material wall is of shallow channel form in cross-section.

HANS ERIC NILSSON.

References Cited in the flle of this patent UNITED STATES PATENTS Number Name Date 1,380,776 Cobb June 7, 1921 2,416,575 Fontaine Feb. 25, 1947 2,468,999 Pettler May 3, 1949 2,486,324 Rike Oct. 25, 1949 2,527,103 Noack et al Oct. 24, 1950 2,530,375 Cartwright Nov. 21, 1950 FOREIGN PATENTS Number Country Date 445,204 Great Britain Apr. 6, 1936 

